Needle-bar for blindstitch sewing-machines



T. J. HAYES.

NEEDLE BAR FOR BLINDSTHCH SEWING MACHINES.

APPLICATION FILED FEB.21918.

1,334,934. I Patented Mar.23,1920.

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THOMAS J'. HAYES, 0F ROSLINDALE, MASSACHUSETTS, ilLSkiIG-NUB TO FELLING MACHINE COMPANY, OF BOS'JIUN, llIASEtACTEIUSETTS, A CORPORATION OF MAINE.

ieaaeaa Specification of Letters Patent.

Igatented Mar. 23, 1920.

Application filed February 2, 1918. Serial No. 215,020.

To all "Lu/tom it may concern:

Be it known that I, THOMAS J. illness, a citizen of the United States, and resident of Roslindale, county of Suffolk, State of l dassachusetts, have invented an Improvement in Needle-Bars for Blindstitch Sewing-Machines, of which the following de scription, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts. 1

This invention relates to improvements in needle bar mechanisms for sewing machines and more particularly to padding or felling machines in which an oscillating needle bar carries a curved eye pointed needle having a thread groove on its convex side extending substantially from the eye to the shank of the needle.

The principal object of the invention is to provide a needle bar construction which will clamp the needle more firmly than has heretofore been accomplished and which can be made at a minimum cost.

In certain usual constructions the needle bar is provided with an enlarged head having a projecting nose to give an extended bearing for the needle ba shank which is seated in a socket extending into or through said nose and head.

The nose and head is in some instances formed of two separate pieces which are clamped together and hold the needle shank between them, In other constructions the needle bar is slotted from its outer end through the bore which forms the socket for the needle shank well into the neck of the needle bar, a screw extending through one of the bifurcated portions of the head thus formed and engaging screw threads in the other serving to draw the portions of the bifurcated head together so as to clamp the needle shank in its socket.

In thus clamping the needle bar one of the sections of the bifurcated head is likely to be deflected more than the other so that the needle may be improperly positioned in respect to the stitch. forming mechanism. Furthermore the force required to be applied by the screw in thus pressing the relatively thick ends of the needle bar together is so great that oftentimes the operators are unable to clamp the needle tightly in the needl bar b s t 1 In the preferred embodiment of the in vention shown herein the bore for the needle shank extends entirely through the head and nose and the slot extends only from the outer end of the needle bar into said bore, the needle being clamped in its place by a special clamping device which is located in a socket or countersink in the side of the needle has and engages the needle shank directly.

In the present construction the side of the needle shank which is engaged by the clamp ing means may be flattened so aspositively to prevent any rotative movement of the needle shank about the axis of the shank, thus insuring its proper positioning in rela tion to the elements of the complemental stitch forming mechanism.

In my construction as in those previously described the slot extending inwardly from the outer end of the needle bar forms a passage for the thread leading to the guideway in the convexedly curved side of the needle. In the present construction a guiding device is located at the mouth of the slot or passage to prevent the thread from leaving said passage and the guideway in the needle when the slack thread is given cit to permit the loop to go around the bobbin or to be manipulated by such loop forming mechanism as may be comprised in the complemental stitch forming mechanism.

Other objects and features of the invention will m ore fully appear from the following description and the accompanying drawings and will be pointed out in the annexed claims.

The drawings illustrate a preferred. embodiment of my invention as applied to a blind. stitch sewing machine in which the needle oscillates in a plane inclined to the work supporting surface of the work support or to the vertical plane of the line of feed.

In the drawings,

Figure 1 is a view of the portion of the head of the sewing machine illustrating a needle bar embodying my invention mounted to oscillate in a plane inclined to the surface of the work support, also showing the presser foot and the revolving hook with which the needle coiiperates,

Fig. 2 is a detail side elevation of the needle bar embodying my invention,

Fig is a rear view of same,

Fig. 4 is a detail longitudinal median sectional view, and,

manner such as that disclosed in my said prior patent. v

The-body of the needle bar is provided with an extension terminating in a boss 7 which is pivotally connected to a stud 8 upon a link 9 which may be reciprocated by any suitable mechanism for the purpose of oscillating the needle, such for example as that disclosedin my priorpatent aforesaid.

Ahook bracket depending from the hub of the machine carries the usual revolving hook 11 which cooperates with a curved needle 12 carriedin thehead 13 of the needle bar in a manner which will hereinafter be more fully. disclosed and which forms the substance of my present invention.

In the present construction, as in certain usual forms of needle bars the head 13 of the needle bar is enlarged and has an extension or nose 14: which provides an extended bearing surface for the shank of the needle. In constructions heretofore 'made the head and nose of the needle bar have been made in two pieces or if made in a single piece the head and nose have been bifurcated, the slot forming the bifurcation extending through both the head and nose and well into the neck portion 15 of the needle bar. V

In these constructions complementary grooves upon the sections of the head. and nose embrace opposite sides of-the needle bar shank and the shank is clamped in place by screws which draw the sections or the.

bifurcated end portions together. In such constructions the needle bar shank exerts'a wedging action against the I walls of the "slot as the curved needle is forced into engagement with the goods so that the parts must be clamped together with great force in order to hold the needle firmly in place. Furthermore in using such constructions there is. usually no abutment for the end of the needle bar shank-and care is required in properly positioning the needle. The present invention contemplates the provision of means for more accurately positioning the needle bar shank in the needle bar and means for retaining the same in position which will clamp the needle bar shank more firmly without requiring so great an exertion upon the part of the operator.

In the preferred mechanism illustrated in the accompanying drawings the head and nose of the needle bar are provided with a bore 16 extending centrally through the nose and head to receive and fit tightly the shank 17 of the needle 12. A slot 18 extends from the outer central portion of the head into the bore 16 but does not cross said bore, this slot 18 providing a thread passage or guideway leading to the thread groove in the convexedly curved side of the needle 12. A pin or stud 19 crossing the bore 16 in the rear portion of the head serves to engage the end of the needle shank and provides means for accurately positioning the needle.

In order to clamp the shank of the needle in the needle bar, the side of the needle bar is provided with a recess or countersink the base of which communicates with and eX- tends slightly beyond the side of the bore 16 so that a portion of the shank of the needle will be exposed and project above the base of said recess. Any suitable clamping instrumentality may be placed in the recess to engage the shank of the needle.

In the preferred embodiment of the invention illustrated herein the clamping means comprises a disk or button 20 havin a fiat needle engaging face 20 which extends nearly across the end face of the button. The button is provided with a central aperture having screw threaded walls adapted to be engaged by the threads of a machine screw 22 which passes through the opposite section of the bifurcated end of the needle bar. The disk or button 20 has opposite to the portion 20 of its face which engages the shank of the needle, a rib 23 which projects beyond the plane of the face 21 and forms a fulcrum for the button so that when the screw 22 is set up a heavy pressure may be applied directly to the shank of the needle.

The disk or button 20 may be prevented from turning by a pin 25! passing through a suitable aperture in said button into a socket in the needle bar.

In this needle bar construction as in usual forms of needle bar constructions the slot 18 forms a passage for the thread which leads directly to the guiding groove in the curved outer surface of the needle and the stud 19 which is engaged by the end of the needle shank provides a guide for the running thread which prevents it from engaging the end of the needle shank and becoming chafed thereby.

In order to insure the retention of the thread in the passage 18 and guide groove in the needle a suitable guide is provided adjacent the end of the slot 18. This guide desirably is in the form of a plate 25 having athread eye therein With a slot 27 leading to said eye to facilitate the threading of the machine. The plate may be secured to the needle bar head in any suit able manner as by a screw 28 and may be QI'O'VGE'lteQl from lateral. movement by a pin 4 29 extending through said plate 25 into the needle bar.

The end portion of the needle bar may be cut away as at 30 so that the guide plate 25 will be spaced a sui'licient distance from the needle bar to permit the ready introduction of the needle thread into the threading slot 27.

The guide plate 25 preferably is sopositioned as to lie entirely within the arc traversed by the needle bar so as to avoid the iiiossibility of injuring the hands of the operator, an accident which frequently occurs in machines in which the guide projeets beyond the end of the needle bar.

it will be observed that the needle bar mechanism disclosed herein is of an exceedingly simple construction, that the strength and rigidity of the needle bar is preserved, that means are provided for insuring the proper positioning of the needle and finally a more positive clamp provided than has heretofore been used which Will insure the preservation of the alinement of the needle.

It will be understood that the clamping mechanism disclosed herein may be used in other types of needle bar and in other relations within the spirit and scope of the following claims.

Having thus described my invention What I claim as new and desire to secure by Letters Patent is;

1. A needle bar having an integral head bored to receive the shank of a needle and provided with a recess located transversely of and communicating with said bore where by a section of the needle shank will projeet into and extend across said recess, a clamping member in said recess fulcrumed upon the bottom Wall of said recess and having a needle engaging face and means located between the fulcrum and the nee dle engaging face for applying pressure to said clamping member.

2. A needle bar having an integral head and nose bored to receive the shank of a. curved eye pointed needle having a thread groove in its convex side, said head being slotted from the outer end to the bore only to provide a thread. passage leading to the thread groove of the needle, one side of said head having a recess extending into said bore and a needle clamping button in said recess, a screw extending through said head and engaging said button adapted to force the button against the shank of the needle and thereby clamp the same firmly in place.

3. A needle bar having an integral head and nose bored to receive the shank of a curved eye-pointed needle having a thread groove in its convex side, said head being slotted from the outer end to the bore only toprovide a thread passage leading to the thread groove of the needle, one side of said head having a recess extending into said here and a clamping button in said recess having a rib on its needle shank engaging face dinmetrically opposite to the portion which engages the shank of the needle, said rib forming a fulcrum for said button and a screw extending axially into said button adapted to cause said button to clamp the shank of the needle firmly in place.

t. A needle bar having an integral head and nose bored to receive the shank of a curved eye pointed needle, one side of said head having a recess extending into said bore, a clamjping member in said recess having a flat face to engage the shank of the needle and an offset face or rib lying in a di'lferent plane and a screw extending centrally through said clamping}; member intermediate of said rib and the surface of the face which engages the shank of the needle.

5. A needle bar having an integral head and nose bored to receive the shank of a curved eye pointed needle, one side of said head having a recess extending into said bore, a clamping member in said recess having a. flat face to engage the shank of the needle and an offset face or rib lying in a different plane, a screw extending centrally through said clamping member intermediate of said rib and the surface of the face which engages the shank of the needle, and a pin extending through said clamping member into the head adapted to prevent rotation of said clamping member in said recess.

6. A. pivoted needle bar having a head and an integral nose bored to receive the shank of an eye-pointed needle having a thread groove in its convex side, said head and nose having an open slot forming a thread passage in alinement with and lead ing to the upper end of the thread groove in said needle, clamping means to engage the shank of said needle and secure the same firmly in place in said head and nose, and a thread guiding member overlying the end of said slot and terminating within the sweep of the needle bar.

7. A needle bar having an integral head and nose bored to receive and fit the shank of a needle, said head being provided with a recess located transversely of and co1nmunicating with said bore whereby a section of the needle shank Will project into and extend across said recess, a clamping member in said recess, means for causing said clamping member firmly to engage said needle shank and means for engaging the end of said needle shank .whereby the same may be quickly and accurately positioned.

8. A needle bar having an integral head and nose bored to receive the shank of a curved eye-pointed needle having a thread guide on its convex side, said head and nose being slotted from the outer end to the bore to provide a thread passage leading to the thread groove in said needle, a pin extending transversely across said slot and a portion of said bore forming an abutment for the end of the needle and providing a thread guide 111 said slot, a recess in the side of said head extending" into said bore, a clamp- THOMAS J. HAYES. 

